SEOUL, Sept. 28 (Yonhap) -- The main opposition Liberty Korea Party (LKP) said Friday it plans to file a complaint against a vice finance minister in a tit-for-tat move after the ministry requested a prosecution probe into its lawmaker over a budget records leak.

Rep. Shim Jae-chul of the party and his aides are being probed over allegations that they accessed digital files on the fiscal budget and other confidential state statistics without authorization.

His office was raided last week, drawing angry reaction from Shim, who said his aides discovered documents about illicit spending by those who accompanied President Moon Jae-in on an overseas trip. The finance ministry lodged a complaint against Shim on Thursday.

Kim Sung-tae, the floor leader of the LKP, said that his party plans to fight back with a complaint of its own against Vice Finance Minister Kim Yong-jin.

"It is absurd that (the government) filed a complaint with prosecutors against an opposition lawmaker over what occurred in the process of securing data ahead of a parliamentary audit," Kim said at a meeting with party officials.

He vowed to thoroughly review details about what's spent by the presidential office Cheong Wa Dae and the government in the name of business operational expenses.

"If there was room for suspected misuses, we will ask prosecutors to investigate all of those who were suspected of misappropriating public funds and embezzling them."

Shim claimed Thursday that Cheong Wa Dae was accused of spending some 240 million won (US$215,750) in operational expenses improperly at nighttime and on weekends between May 2017 and August 2018.

The presidential office rebutted his claim Thursday, saying that it is inevitable for its officials to handle state affairs beyond business hours, given that the nature of their work requires urgency and security and trade issues call for around-the-clock readiness.

Meanwhile, the ruling Democratic Party said that it will petition the parliamentary ethics committee to look into Shim.

"It was another act of crime that he disclosed details about Cheong Wa Dae's expenses even without checking basic facts, on top of illegal data leaks," Hong Young-pyo, the floor leader of the DP, said at a meeting with senior party officials.